You can place an "RP House" sign on the mines if you have a dupe.
Hits can be claimed in a "RP House" as well as wanted people or people with illegals arrested, an RP House stops you from being raided for specific reasons but not things such as raiding to arrest a wanted person.

As for any raidables placed inside while there is a sign, the person who places something such as a charger or printer is in the wrong, and not the one who placed the sign.

You cannot raid the mines like a conventional base, yes you can kill a miner who has a printer in the dupe but as a charger has no identifiable owner then it's rdm, In Emmits case attempted RDM as he reduced the HP of those inside.